Draft gear



Oct. 12, 1943. R. M. NELSON DRAFT GEAR Filed. Oct. 3, 1941 Z Sheets-Sheet l Oct. 12, 194.3. R. M. NELSON DfiAFT GEAR Filed Oct. 3, 1941 '2 Sheets-Sheet 2 awe/who's RoberfiMNZ-son,

Patented Oct. 12, 1943 v UNITED STATES PATENT OFFKIE 2,331,620 r nnAr'r GEAR. Robert M. Nelson, Evanston, Ill., assignor to Peer less Equipment Company, Chicago, 111., a cornotation of Delaware Application: October 3, 1941, Serial No. 413,548

2 Claims; (01. 213-24) This invention relates to railway draft gears of the general type comprising a casing, friction shoes therein, resilient means reacting from the casing'forwardly' upon said fraction shoes,

and a wedge element for exerting force rear- 5 Figure 6 is a front end view of the gear shownv Wardly and outwardly upon said fraction shoes in Fig. 5; and

in response to draft and buffing forces imposed Figure 7 is a perspective view of one of the on the gear to cause said shoes to frictionally .liners employed in the gear shown in Figs, 5 resist said forces. and 6.

In draft gears of the general type mentioned 10- Referring to the drawings in detail, first with it is desirable to provide'means to prevent-stickparticular reference to Figs. 1 t 4, lil designates ing of the friction shoes'i n rearwardly disposed a substantially cylindrical casing open at its positions after release of draft or buffing forces front end and closed at its rear end; ll designate imposed on the gear, as in that event the gear is friction'shoes disposed in the front end portion ineffective to absorb shocks incident to subseof said casing;' l2 designates resilient means quent draft or buffing forces imposed thereon and interposed between the rear ends of said friction if the friction shoes are jarred loose, as usually shoes and the rear wall [3 of said casing and happens, the gear suddenly expands with a Very reacting from said' rear wall upon said friction undesirable hammer-like action. Also, it is deshoes to tend constantly to urge them forwardly sirable in such gears to provide for initial subrelative to said casing; and M'designates a wedge stantially free rearward movement of the fricelement for acting rearwardly and. outwardly tion shoes relative to the casing resisted only by upon the front ends of said friction shoes in the resilient means exerting force forwardly upon response to draft and buffingl'forces imposed on the friction shoes in order to avoid sudden and the gear; l2*- designates'resilient means interharsh absorption of draft and buffing forces imposed between the rear end of the casing 10 and posed on the gear and to cause the gear to absorb the wedge element l4 and racting from the rear such forces gradually and smoothly. Accordingly, end of said casing directly forwardly upon said the general object of the present invention is to Wedge element to assist the resilient means I2 provide a draft gear of the type mentioned emin effecting forward movement of said wedge bodying simple, practical means to insure against element and release of the same from the fricsticking of the friction shoes in rearwardly distion shoes ll independently of the action of the posed positions and to permit substantially free resilient means l2 upon the rear ends of said initial rearward movement of the friction shoes friction shoes, all as is common and well known resisted only by the resilient means which exerts in the art. force forwardly against'said shoes. In draft gears of the type under consideration With theforegoing and other objects in view, the friction shoes usually cooperate directly with which will become more fully apparent as the rearwardly and inwardly inclined interior faces nature of the invention is better understood, the of the casing at the frontend thereof. According consists in a draft gear of the general type to the present invention, however, liners l5 are mentioned embodying the novel features of con- 40 interposed'between the friction shoes H and the struction, combination and arrangement of parts casing ill; theouter faces of said friction shoes as will be hereinafter more fully described, illussire; as usual, inclined rearwardly' and inwardly; trated in the accompanying drawings and dethe inner faces of saidliners are inclined rearfined in the appended claims. Wardly and inwardly corresponding to the in- In the accompanying drawings, wherein like clination of the outer faces of said friction shoes characters of reference denote corresponding and are engaged by the said outer faces of said parts in related views: friction shoes, and the outer faces of said liners Figure 1 is a central, vertical, longitudinal secand the inner faces of the casing which they ention through a draft gear constructed in acgage are parallel to the longitudinal axis of said cordance with one practical embodiment of the casing. Moreover, the casing H) is provided with invention. front and rear stop elements I6 and I7, respec- Figure 2 is a. cross section on the line 22 tively, engageable by the front and rear ends of Fig. 1. of the liners l5, and said liners are of lesser Figure 3 is a fragmentary, longitudinal section length than the distance between said stop eleon the line 3--3 of Fig. 2. mentswhereby they are capable of limited longi- Figure 4 is a perspective View of the rear end portion of one of the liners.

Figure'5 is a view similar to Fig. 1 illustrating an alternative embodiment of the invention.

tudinal movement relative to the casing III. Furthermore, the coefficient of friction between the liners IS and the casing ID is suitably made as low as possible and, in any event, is lower than the coeflicient of friction between said liners and the shoes II, and coil springs l8 or other suitable resilient means, separate from the resilient means 12, preferably are interposed between the rear ends of the liners l5 and the rear stop elements H to tend constantly to urge said liners forwardly relative to the casing I0.

It is understood, of course, that in accordance with common practice in the art, stop means are provided to limit rearward movement of the casing l and forward movement of the wedge element 14; that a yoke is associated with the cas ing III for transmitting draft forces forwardly thereto, and that a coupler butt cooperates with the wedge element l4 for transmitting bufiing forces rearwardly thereto. Accordingly, either draft or boring forces imposed on the gear are effective to cause the wedge element H to exert force rearwardly and outwardly upon the friction shoes H counter to the force exerted forwardly upon said shoes by the resilient means l2.

Accordingly, since normally the liners l5 are held in their forwardmost positions by the springs I8, and since the outer faces of said liners and the interior faces of the casing l0 whichthe'y engage are parallel to the axis of the casing II and have a low coefiicient of friction, at least as compared with the coefficient of friction between the inner faces of said liners and the friction shoes H, it is apparent that upon the wedge element l4 being subjected to rearwardly directed draft or buffing forces, the shoes H and the liners" will be moved rearwardly relative to the casing resisted substantially only by the resilient means l2, l2 and I8 until the rear ends of the liners abut the rear stopelemerits l1, and that thereafter any further rearward movement of said shoes will be resisted by the frictional cooperation of the same with said liners. Likewise, it is apparent'that upon release of draft or bufling forces upon the wedge element H and in the event of tendency of the friction shoes H to stick to the liners 15, said liners, said shoes and said wedge element will be moved forwardly by the resilient means I2, I2 and 18 until said liners are suddenly stopped by engagement of their front ends with the front stop elements N, which st pping, combined with the inertia of the wedge element and the force of the resilient means l2, will result in loosening of the shoes.

The amount of substantially free rearward movement of the friction shoes I I relative to the casing l0 may, of course, be variably predetermined by a proper selection of difference in length between said shoes and the space between the stop elements [6 and I1. Moreover, while the springs I8 are illustrated in the present instance as being housed in bores [9 in the stop elements l8 whereby they are retained in operative relationship to the liners l5, it is apparent that said springs, or their equivalents, may be arranged in any other manner to accomplish their function of assuring return of the liners I5 to their forwardmost positions and of maintaining them normally in their forwardmost positions against the stop elements I6 when the gear is relieved of draft or buffing forces. In this connection it will be apparent that the springs l8 are not essential, as the frictional cooperation between the friction shoes II and the liners IE will result in said liners being carried forwardly with said friction shoes whenever, after operation of the gear, the draft or bufiing forces imposed thereon are released. Accordingly, Figs. 5 to 7 of the drawings illustrate a construction which is the same as the Figs. 1 to 4 construction, except that it is devoid of springs such as the springs #8.

A :novel and advantageous feature of the invention is that the liners [8- have, or may have, bearing throughout the area of their outer faces with the casing l0, and that said casing is in no way weakened by recessing or the like in order to adapt the same to accommodate said liners for limited longitudinal movement relative thereon. On the contrary, the stop elements l6 and H serve to reinforce the casing.

. Without further description it is thought that the features and advantages of the invention will be readily apparent to those skilled in the art, and it will of course be understood that changes in the form, proportion and minor details of construction may be resorted to, without departing from the spirit of the invention and scope of the appmded claims I claim:

1. A draft gear comprising a casing provided with inwardly extending front and rear spaced apart stop elements, a plurality of friction shoes having downwardly and inwardly inclined outer faces, a wedge element nested within and cooperating with the friction shoes, spring means associated with the shoes and wedge element, a reciprocal metal liner interposed between each shoe and the inner wall of the casing and having an inclined face registering with the inclined face of the shoe, each of said liners being shorter in length than the distance between the said stop elements and movable therebetween and thereagainst, and a positioning spring for each of said liners, the said spring being seated within the casingand arranged to exert a pressure forwardly against the liner with which it is associated. v 2. A draft gear as set forth in claim 1 in which the rear stop elements are provided with housing recesses or bores to accommodate and hold the positioning springs for each of the liners.

ROBERT M. NELSON. 

